跳至主要内容

Effect of Emulsifier Concentration on the Oxidation of an O/W Emulsion Prepared from Canola Oil

In most cases, oils and fats are present as emulsions, such as water-in-oil (W/O) emulsion (e.g. margarine and butter) or oil-in-water (O/W) emulsion (e.g. beverages, milk, and fresh cream). Some studies have shown that oxidative deterioration of foods containing oils and fats may be affected by light, temperature, metals, or peroxide contained in food. In fact, oxidative deterioration is a large economic concern in the food and preventing the oxidation of emulsion is of vital importance for the food industry.

In this study, the effect of different concentrations of Tween 20 (0.5, 2.5, 5.0, 10 w% vs. oil) on the oxidation of canola oil O/W emulsion was investigated. Oxidation was conducted at 34°C in the dark and accelerated using 2,2-azobis (2,4-dimethylvaleronitrile) (AMVN) and 2,2’-azobis (2-methylpropionamidine) dihydrochloride (AAPH) as radical generators. Peroxide value (PV, mEq/kg) was monitored as generation of the primary oxidation compound. Tocopherol content of oil was analyzed by high performance liquid chromatography (HPLC). Particle size of emulsion was measured using an inverted optical microscope (200x), and calculated with “Image J” software (National Institute of Mental Health, Bethesda, MA).  

The results showed that PV was suppressed by Tween 20 in a dose-dependent manner in both emulsion system using AMVN and AAPH, and the tendency of suppression was clearer in the system using AMVN than in that using AAPH. Contrarily, there were no significant differences in PV when emulsions were prepared with tocopherol-stripped oil. The particle size of emulsion droplets were also consistent among emulsions prepared. However, tocopherol contents at lipid phase of the emulsions prior to oxidation decreased with concentration of Tween 20.

In conclusion, although the effect was modest, excess amount of Tween 20 modified the antioxidant efficacy of tocopherol in a dose-dependent manner. The speculation is that Tween 20 can help tocopherol to migrate from the lipid phase to the oil-water interphase, where the oxidation occurs. Further research to define the optimum combination of oil, water, and emulsifier is required.


Article by Yukihiro Yamamoto and Rino Misawa, from Prefectural University of Hiroshima, Shobara, Japan.

Full access: http://mrw.so/517D53

Image by Indirect Heat, from Flickr-cc.

评论

发表评论

此博客中的热门博文

Electron Spin and Proton Spin in the Hydrogen and Hydrogen-Like Atomic Systems

Read full paper at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=52202#.VIj7tMnQrzE Author(s) Stanisław Olszewski * Affiliation(s) Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland . ABSTRACT The mechanical angular momentum and magnetic moment of the electron and proton spin have been calculated semiclassically with the aid of the uncertainty principle for energy and time. The spin effects of both kinds of the elementary particles can be expressed in terms of similar formulae. The quantization of the spin motion has been done on the basis of the old quantum theory. It gives a quantum number n = 1/2 as the index of the spin state acceptable for both the electron and proton ...
发表评论
阅读全文

Remarks on the Complexity of Signed k-Domination on Graphs

Read  full  paper  at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=53574#.VMnXsCzQrzE Author(s)    Chuan-Min Lee 1 , Cheng-Chien Lo 1 , Rui-Xin Ye 2 , Xun Xu 2 , Xiao-Han Shi 2 , Jia-Ying Li 2 Affiliation(s) 1 Department of Computer and Communication Engineering, Ming Chuan University, The First American University in Asia, Taoyuan, Taiwan, Chinese Taipei . 2 Department of Electronic Information Engineering, Fuzhou University, Fuzhou, China . ABSTRACT This paper is motivated by the concept of the signed k-domination problem and dedicated to the complexity of the problem on graphs. For any fixed nonnegative integer k, we show that the signed k-domination problem is NP-complete for doubly chordal graphs. For strongly chordal graphs and distance-hereditary graphs, we show that the signed k-domination problem can be solved in polynomial time. We also show that the problem is linear-time solvable for trees, interval graphs, and chord...
发表评论
阅读全文

A Review of Technical Requirements for High Penetration of Wind Power Systems

Read full paper at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=52361#.VJN8VcCAM4 Author(s)    Yuan-Kang Wu 1 , Tung-Ching Lee 2 , Ting-Yen Hsieh 2 , Wei-Min Lin 2 Affiliation(s) 1 Department of Electrical Engineering, National Chung-Cheng University, Chiayi, Taiwan . 2 Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan . ABSTRACT Renewable portfolio targets have been established in many regions around the world. Regional targets such as 20% renewable energy by year 2020 are not uncommon. As the levels of wind power penetration increase, there are many power system impacts. This work investigated possible challenges and technic...
发表评论
阅读全文